We’d like to goal our agents on email first response times - but measuring the time from when a case is first assigned to the agent and when they respond, rather than from when the customer first emailed and the agent responded.

Example:  

A customer emails us.  2 hours pass before an agent is assigned the case.  The agent then responds an hour later.  For measuring the agent’s performance, we’d want to capture the 1 hour difference between assignment and the agent’s first response to the customer, rather than the 3 hours between when the customer first reached out and the agent first responded back.

Basically, we want to goal our agents based on what’s in their control.  We are also tracking the overall First Response Time because at the end of the day that’s the customer’s experience- but we’re treating this as a team level metric influenced by things like staffing levels, product issues and the like - many things outside of an individual agent’s control.

Is this possible?  How would we do it?  Thank you!